Method for manufacturing laminate for honeycomb structure

ABSTRACT

A method and apparatus of manufacturing laminate for honeycomb structure. The invention includes first and second adhesive agent applying units, each of which applies an adhesive agent to a material strip in parallel strips, first and second pressing rolls corresponding to each of said adhesive agent applying units, and a layering table reciprocated by a predetermined stroke. The second stripes of the adhesive agent are displaced transversely by a half pitch from the first stripes of the adhesive agent. The adhesive agent applying units and the pressing rolls are disposed immediately above the layering table and the rolls press the material strip being fed onto the layered material strip, and are moved between an operating position and an un-operating position with relation to the movement of the layering table. The layering table is movable and a roll stand housing the pressing rolls moves in a direction opposite to that of the layering table.

BACKGROUND OF THE INVENTION

This invention relates to a method and an apparatus for manufacturinglaminate for honeycomb structures and more particularly it relates to amethod and an apparatus capable of easily and continuously manufacturinglaminate for honeycomb structures comprising precisely formed cells andhaving excellent functional features such as a good air permeability.

PRIOR ART

Conventional methods and apparatuses for manufacturing laminate forhoneycomb structures are generally classified into two types, those of afirst type that involve steps of applying an adhesive agent to amaterial strip being unwound from a roll, drying it, cutting the stripto sheets of a unit length and bonding them together to form laminatefor honeycomb structure and those of a second type that form a strip oflaminate for honeycomb structure simply by bonding a number of componentstrips and winding it up onto a roll.

Additionally, there are methods and apparatuses of a third type, or amodified first type, where the applied adhesive may or may not be driedbefore the rolled material strip is cut to sheets of a unit length toform a laminate for honeycomb structure.

Technologies for the above described first, second and third groups aredisclosed in Japanese Patent Laid-Open Nos. 224825/88, 157847/85 and255422/85 and Japanese Patent Publication 30184/81 respectively.

In any of the above conventional methods and apparatuses, an emulsiontype adhesive agent containing water or a solvent other than water as adiluent or a hot-melt type agent containing synthetic resin that becomesadhesive when heated and/or pressurized is normally employed.

The method and apparatus according to said Japanese Patent Laid-Open No.224825/88, which belong to the first type, require complicatedmechanical and electric means for establishing and maintaining a givenratio of the rate of revolution of a roll of a strip-shaped material towhich an adhesive agent being applied to that of another roll of thematerial which is being cut in order to produce sheets of the materialof a given unit length and, additionally, steps for drying the appliedadhesive agent.

The complicacy of this technique makes the overall process ofmanufacturing laminate for honeycomb structure rather inefficient.

Japanese Patent Laid-Open No. 157847/85 proposes a technique belongingto the second category of producing a roll of a strip-shaped multilayerstructure wound up on a drum by bonding a number of component strips,which is then dried and cut to sheets of unit size. This techniquerequires an apparatus having a complicated structure for aligning lineson the component strips in order to bond them together correctly and theadhesive agent used to bond the strips together requires to be driedwell, making the technique as inefficient as the first one.

Each of the techniques belonging to the third type and disclosed inJapanese Patent Publication No. 30184/81 and Japanese Patent Laid-openNo. 255422/85 entail complicated means for aligning sheets to be layeredand cutting them to a unit length, making the overall process ofmanufacturing multilayer structures also rather complicated andcumbersome.

Any of the above described conventional methods and apparatuses thuscomprise steps of drying the applied adhesive and cutting multilayeredor single-layer strips to a unit length, requiring time from theapplication of adhesive agent to the formation of a multilayer structureand the operation of bonding component strips or sheets together andforming a multilayer structure cannot be carried out immediately afterthe application of adhesive agent.

Thus, if component strips or sheets for forming a honeycomb structureare composed of thin and soft or coarse tissues that are permeable togas and water, any of the above quoted adhesive agents applied to a sideof a strip can easily pass therethrough to the other side so that thebonded strips may become flat to form a single plate that may look likea plywood.

If a molten hot-melt type adhesive agent is applied to a side of a stripof a thin and soft or coarse material in an attempt to prevent it frompassing to the other side, the long time spent from the application ofthe adhesive agent to the completion of the multilayering operationreduces the adhesiveness of the agent to consequently produce ahoneycomb structure which is poor in stoutness. Additionally, theapplied adhesive agent can easily pass to the other side to flatten thehoneycomb structure once it is heated and/or put under pressure.

Furthermore, any of the above cited techniques involves cumbersome stepsof detecting cutting positions on a strip, aligning the edges ofprepared sheets and multilayering them neatly to a given number oflayers, making it very difficult to manufacture high precision honeycombstructures.

When an adhesive agent is applied to each component sheet in a number ofstripes and sheets are put together to form a multilayer structure, theycan be swerved from one another to show a completely irregulararrangement as they are moved along a curved line from one work stationto another.

In view of the above described problems and other problems of the priorart, it is therefore an object of the present invention to provide amethod and an apparatus for manufacturing high quality laminate forhoneycomb structure at a high yield by relatively simple means andwithout causing them to lose the honeycomb structure and become flateven if a thin and soft or coarse material which is permeable to gas andwater and therefore through which an adhesive agent can easily pass isused.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, the above objectis achieved by providing a method of manufacturing laminate forhoneycomb structure, comprising the steps of; (a) feeding a materialstrip by a predetermined length to the uppermost surface of folded andlayered material strip disposed on a layering table by forwardly movingsaid layering table by a stroke corresponding to said length; (b)applying a plurality of first stripes of an adhesive agent either to anupper surface of the layered strip on said layering table or a lowersurface of the material strip being fed; (c) immediately pressing thematerial strip being fed to the layered strip; (d) folding a rear end ofsaid length of the material strip; (e) feeding the material strip by thelength to the surface of folded and layered material strip disposed onthe layering table by moving backwardly a predetermined table by saidstroke; (f) applying a plurality of second stripes of an adhesive agentto said surface, said second stripes being displaced transversely by ahalf pitch from the first stripes of the adhesive agent; (g) immediatelypressing the material strip being fed to the layered strip; (h) foldingthe rear end of said length of the material strip; and (i) repeating theabove (a) to (h).

Preferably, said layering table is reciprocated by the predeterminedstroke, and means for feeding the material strip and means for applyinga plurality of stripes of the adhesive agent are moved relative to saidlayering table.

Still preferably, a plurality of stripes of the adhesive agent areapplied to a lower surface of the material strip being fed.

Alternatively, a plurality of stripes of the adhesive agent are appliedto an upper surface of the layered strip on said layering table.

According to another aspect of the present invention, the above objectis achieved by providing an apparatus for manufacturing laminate forhoneycomb structure; comprising a unit for continuously feeding amaterial strip, and a layering table; said unit including a feedingorifice, first and second adhesive agent applying units, and first andsecond pressing rolls corresponding to each of said adhesive agentapplying units; said layering table being moved forwardly and backwardlyrelative to the feeding orifice by a predetermined stroke; said adhesiveagent applying units applying a plurality of first and second stripes ofan adhesive agent to either to an upper surface of a layered strip onsaid layering table or a lower surface of the material strip being fed;said second stripes of the adhesive agent being displaced transverselyby a half pitch from the first stripes of the adhesive agent; saidpressing rolls being disposed on said layering table for pressing downthe material strip on the layering table; said first adhesive agentapplying unit and said first pressing roll being moved between anoperating position and an un-operating position, said second adhesiveagent applying unit and said second pressing roll being moved between anoperating position and an un-operating position; when said layeringtable being moved forwardly, said second adhesive agent applying unitand said second pressing roll being in the operating position, and saidfirst adhesive agent applying unit and said first pressing roll being inthe un-operating position; and when said layering table being movedbackwardly, said first adhesive agent applying unit and said firstpressing roll being in the operating position, and said second adhesiveagent applying unit and said second pressing roll being in theun-operating position.

Preferably, said unit for continuously feeding a material strip isreciprocated by the predetermined stroke relative to said layeringtable.

Still preferably, an applicator of the adhesive agent applying unit isdisposed on the way to feed the material strip.

Alternatively, an applicator of the adhesive agent applying unit isdisposed on the surface of the layered strip.

With a method and an apparatus according to the invention, a materialstrip fed through a set of tension rolls and other rolls at a given rateis folded by every predetermined length on a layering tablereciprocating by a stroke corresponding to said length without being cutafter an adhesive agent has been applied thereto so that the operationof applying an adhesive agent to a length of the material strip andbonding it to portions thereof that have already been layered can berepeated in a relatively simple and well controlled manner by simplycontrolling the turning points of the reciprocating layering table andclamping the layered material strip along the folded lines thereof. Withsuch an arrangement, layers of the layered material strip do not need tobe accurately aligned along the folded lines and therefore a method andan apparatus according to the invention is exempted from a cumbersomeoperation of aligning unit sheets before forming a laminate forhoneycomb structure.

Thus, with a method and an apparatus according to the invention, amolten hot-melt type adhesive agent having a relatively high viscositycan be, if used, prevented from passing through a material strip from aside to the other thereof and, therefore, even if the material strip ismade of a thin, soft and coarse material, a hot-melt type adhesive agentcan be applied to it by adhesive agent applying units without the riskof passing through the material strip, which can be bonded togetherimmediately after the application of the bonding agent, using a backuproll or a layering table as a support before the adhesive agent iscooled to deteriorate its performance.

The applied hot-melt type adhesive agent is rapidly cooled and hardenedas it is brought to contact with the material strip so that it would notpass through the material strip from a side to the other thereof if thematerial strip is highly permeable to gas and water.

Additionally, since the method of the present invention does not involveany hot press operation after the formation of a laminate for honeycombstructure nor the use of a diluent for regulating the viscosity of thesolvent of the adhesive agent, high precision laminate for honeycombstructures may be manufactured by using very thin material strips thatare permeable to gas and liquid.

When one or more than one combinations of an adhesive agent applyingunit and a pressing roll are arranged immediately above the layeringtable and housed in a unit for continuously feeding a material stripdisposed above the layering table or in a roll housing stand which isintegrally formed with and operated to move in synchronism with andrelative to the layering table, the operating speed of the layeringtable relative to the roll housing stand can be increased to raise therate of processing the material strip and hence the efficiency ofmanufacturing laminate for honeycomb structures.

When the adhesive agent applying sections of the adhesive agent applyingunits are arranged close to the respective pressing rolls and above thelayering table, the time from applying the adhesive agent to bonding anadditional length of the material strip to the layered portions thereofcan be reduced to further improve the efficiency and productivity of thelaminate for honeycomb structure producing operation and, stilladvantageously, the component layers of the laminate for honeycombstructure can be bonded firmly with one another with a reduced amount ofhighly viscous hot-melt type adhesive agent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of an embodiment of apparatus formanufacturing laminate for honeycomb structures of the invention.

FIG. 2 is a schematic front view of another embodiment of apparatus formanufacturing laminate for honeycomb structure of the invention.

FIG. 3 is a schematic front view of still another embodiment ofapparatus for manufacturing laminate for honeycomb structure of theinvention.

FIG. 4 is a schematic front view of still another embodiment ofapparatus for manufacturing laminate for honeycomb structure of theinvention.

FIG. 5 is a schematic plan view of a material strip to which an adhesiveagent is applied in parallel stripes.

FIG. 6 is a schematic plan view of a material strip similar to FIG. 5but showing parallel stripes of adhesive agent displaced by a half pitchrelative to those of FIG. 5.

FIG. 7 is a schematic elevational view of a multilayer structureprepared by alternately layering strips as illustrated in FIG. 5 andthose as illustrated in FIG. 6.

FIG. 8 is a schematic perspective view of the laminate for honeycombstructure obtained by vertically expanding the structure shown in FIG.7.

FIG. 9 is a schematic plan view of a material strip to which an adhesiveagent is applied in parallel stripes running rectangularly relative tothe longitudinal direction of the material strip.

FIG. 10 is a schematic plan view of a material strip similar to FIG. 9but showing parallel stripes of adhesive agent displaced by a half pitchrelative to those of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the present invention will be described by referring to theaccompanying drawings that illustrate preferred embodiments of theinvention, but the scope of the invention is not limited to theembodiments.

FIG. 1 is a schematic lateral view of the first preferred embodiment ofthe invention comprising a roll stand 1 rotatably carrying a roll 2 of amaterial strip 4, a continuous material strip feeding unit 3 and alayering table 12. The continuous material strip feeding unit 3 includesa mechanism for continuously feeding the material strip 4 from the roll2, a pair of adhesive agent applying units 5, 6 which will be describedhereinafter, a pair of back-up rolls 7, 8 and a pair of pressing rolls19, 20. The layering table 12 can reciprocate at a predetermined strokerelative to said pressing rolls 19, 20. The material strip 4 is foldedand pressed to form a multilayer structure by the selective operation ofthe continuous material strip feeding unit 3, the movement of thelayering table 12 and the selective use of the pressing rolls 19, 20.

A pair of guide rollers 10, 11 are arranged at an upper portion of thecontinuous material strip feeding unit 3 in order to correct anyswerving motion of the material strip 4. The back-up rolls 7, 8 and theadhesive agent applying units 5, 6 are disposed below said guide roller11. Each of the back-up rolls 7, 8 is facing the respective adhesiveagent applying units 5, 6 and the back-up roll 7 acts with the adhesiveagent applying unit 5 and the back-up roll 8 acts with the adhesiveagent applying unit 6. The material strip 4 is fed between the adhesiveagent applying unit and the back-up roll.

An adhesive agent is applied to a side to be laminated of said materialstrip 4 in the form of parallel stripes to form a laminate for honeycombstructure. The layering table 12 and the adhesive agent applying unit 5or 6 are selectively used. When the layering table 12 is moving in thedirection of XL, the adhesive agent will be applied to a side 16 of thematerial strip 4 by the first adhesive agent applying unit 6 and thecorresponding first back-up roll 8. The side 16 to be applied with theadhesive agent is positioned rearwardly. When the layering table 12 ismoving in the direction of XR, the adhesive agent will be applied to aside 17 of the material strip 4, which side 17 is positioned forwardly,by the second adhesive agent applying unit 5 and the secondcorresponding back-up roll 7.

When the adhesive agent applying unit 6 is in its operating position 6Aas indicated by a solid line in FIG. 1, it can apply the adhesive agentto the side 16 of the material strip 4 with the support of thecorresponding back-up roll 8. The adhesive agent applying unit 6 doesnot apply the adhesive agent in its un-operating position as indicatedby a broken line. In the un-operating position, the adhesive agentapplying unit 6 is held away from the back-up roll 8.

Likewise, when the adhesive agent applying unit 5 is in its operatingposition 5A as indicated by a broken line in FIG. 1, it can apply theadhesive agent to the side 17 of the material strip 4 with the supportof the corresponding back-up roll 7. The adhesive agent applying unit 5does not apply the adhesive agent in its un-operating position asindicated by a solid line. When the unit 5 is in the un-operatingposition, it is held away from the back-up roll 7.

The adhesive agent applying units 5 and 6 move between the respectiveoperating positions 5A, 6A and the respective un-operating positions 5B,6B in an alternate manner in response to signals transmitted from thelayering table 12 as a function of the reciprocating motion of the table12.

When the adhesive agent is applied to the side 16, the material strip 4is fed by the guide roller 11, runs along an inclined path as indicatedby a solid line in FIG. 1, and passes between the back-up roll 8 andadhesive agent applying unit 6. A guide roller 14 is arranged near theback-up roll 8. When the guide roller 14 is in its operating position14A as indicated by a solid line in FIG. 1, the material strip 4 may berunning tightly on the outer peripheral surface of the back-up roll 8 infront of the adhesive agent applying unit 6 and therefore the adhesiveagent may be stably applied to the material strip 4. On the other hand,when the guide roller 14 is in its un-operating position 14B asindicated by a broken line, the material strip 4 is not fed to theback-up roll 8 and passes between the back-up roll 7 and the adhesiveagent applying unit 5 to apply the adhesive agent to the side 17. Insuch a case, the guide roller 14 is held back to its retreat position14B as indicated by a broken line.

As described above, the guide roller 14 is selectively moved between itsoperating position 14A and un-operating position 14B depending on themode of adhesive agent applying operation.

Each of the adhesive agent applying units 5 and 6 is provided with anapplicator for applying the adhesive agent on the corresponding side ofthe material strip 4 in the form of parallel stripes. For example, thefirst strips of the adhesive agent are applied to the side 16 of thematerial strip 4 as illustrated in FIG. 5 and the second stripes of theadhesive agent are applied to the side 17 as illustrated in FIG. 6, eachstripe having a width C of 5.8 mm, at a pitch P of 23.1 mm. The secondstrip is transversely displaced by a half pitch in the succeedingoperating mode. The width and the pitch of the stripe is not limited tothe above.

The pressing rolls 19, 20 that are used in combination with therespective adhesive agent applying units 6, 5, and are located at theopposite sides of a material strip feeding orifice 9 of the continuousmaterial strip feeding unit 3 in such a manner that the pressing rollspress the material strip 4 with adhesive agent against the layeredportions 18 of the material strip 4 on the layering table 12. After theadhesive agent is applied to the side 16 by the adhesive agent applyingunit 6 for a predetermined stretch of the material strip 4, such stretchof the material strip 4 is pressed against the layered portions 18 ofthe material strip 4 by the pressing roll 19 located in its operatingposition 19A as indicated by a solid line in FIG. 1. The stretch of thematerial strip 4 is continuously fed onto the layering table 12 by themovement of the layering table 12 in the direction of arrow XL. Thelayering table 12 runs on a track 15 laid on a support structure 13.

The pressing rolls 19 and 20 operates for layering and pressing thematerial strip 4 on the surface of the layering table 12 in theirrespective operating positions 19A and 20A, whereas they are notoperational in their respective un-operating positions 19B and 20B.Therefore, the pressing rolls 19 and 20 move between the respectiveoperating positions 19A, 20A and the respective un-operating positions19B, 20B in an alternate manner as a function of the mode of adhesiveagent applying operation.

Thus, the operation of each of the adhesive agent applying units 5 and 6and the pressing rolls 19 and 20 is so controlled by the signal fromclamping units 21 and 22 disposed at the respective opposite ends of thelayering table that, when the layering table 12 is moving in thedirection of arrow XL, the adhesive agent applying unit 6 for applyingthe adhesive agent to the side 16 (rearwardly positioned) of thematerial strip 4 and the corresponding pressing roll 19 for touching theside 17 (forwardly positioned) to press down the material strip 4 as itis fed along the broken line in FIG. 1 are located in the respectiveoperating positions 6A and 19A and, the adhesive agent applying unit 5and the pressing roll 20 are retreat to their respective un-operatingpositions 5B and 20B.

Now, the operation of the above embodiment having an above describedconfiguration to apply the adhesive agent to a length of the materialstrip 4, to layer and to press it, and to form finally a laminate forhoneycomb structure will be described below.

The material strip 4 pulled out from the roll 2 proceeds along the solidline for side 16 in FIG. 1 and is guided by the guide roller 14. Thematerial strip is supported by the back-up roll 8, and according to adirect application technique, the adhesive agent applying unit 6 isapplying the adhesive agent to the side 16 for a predetermined length inparallel stripes, each stripe having a width C of 5.8 mm, in thelongitudinal direction of arrow A as shown in FIG. 5 at a pitch P of23.1 mm. The stretch of the material strip 4 with the under surface 16is then pressed against the layered portions 18 of the material strip 4by the pressing roll 19 and by the movement of the layering table 12 inthe direction of arrow XL to complete the layering operation for thelength that carries the adhesive agent on the side 16.

In the mode of operation where the layering table 12 move in thedirection of arrow XR, the material strip 4 proceeds along the brokenline in FIG. 1, and the adhesive agent is applied to the side 17 to thelength by the adhesive agent applying unit 5 in parallel stripes at apitch P of 23.1 mm, each stripe C having a width of 5.8 mm, while thematerial strip 4 is supported by the back-up roll 7. The pitch and thewidth of this second stripes of the applied adhesive agent are same asthose of the first stripes of the adhesive agent illustrated in FIG. 5,but the second stripes of the adhesive agent is transversely displacedby a half pitch relative to the first stripes as shown in FIG. 6. Thestretch of the material strip 4 with the under surface 17 is pressedagainst the layered portions 18 of the material strip 4 by the pressingroll 20 while the layering table 12 is moving in the direction of arrowXL, so that a given number of layers are formed to produce a multilayerstructure (laminate for honeycomb structure) as illustrated in FIG. 7.The multilayer structure is cut to a predetermined width D and expandedin the vertical direction H to form honeycomb structure as illustratedin FIG. 8.

When the clamps 21 and 22 disposed at the opposite ends of the layeringtable 12 are set to face to the feeding orifice 9 of the continuousmaterial strip feeding unit 3, the material strip 4 is clamped by theclamps 21, 22, which by turn transmit a clamp signal to switch themoving direction of the layering table 12 as well as the operation ofvarious units and rollers constituting the continuous material stripfeeding unit 3.

In an experiment according to the embodiment, a roll of a material strip4 was prepared by using nonwoven polyester fiber which was permeable togas and water and had a weight per unit area of 40 g/m² and a thicknessof 0.11 mm, and a modified olefin type hot-melt adhesive was applied tothe material stripe 4 in parallel stripes at a pitch P of 23.1 mm, eachstripe having a width C of 5.8 mm, to produce the honeycomb structurehaving a cell size of 10 mm.

FIG. 2 shows a second embodiment of the invention. In this embodiment, acontinuous material strip feeding unit 23 and a layering table 30. Thecontinuous material strip feeding unit 23 includes a pair of adhesiveagent applying units 24, 25 with respective applicators 26, 27 and apair of pressing rolls 28, 29 which are oppositely arranged near afeeding orifice 40 for feeding the material strip 4. The feeding orifice40 is located faced to and above the layering table 30 on which carrieslayered portions 31 of a material strip 4 thereon. The adhesive agentapplying units 24, 25 are disposed close to the pressing rolls 28, 29.

Said pressing rolls 28, 29 operate in an alternate manner as they movebetween respective operating positions 28A, 29A and respectiveun-operating positions 28B, 29B depending on the side of the materialstrip 4 to be applied with an adhesive agent. The adhesive agentapplying units 24, 25 operate in an alternate manner as they movebetween respective operating positions 24A, 25A and respectiveun-operating positions 24B, 25B.

Similar to the first embodiment described above by referring to FIG. 1,the roll stand 1 carries the roll 2 of the material strip 4, whichproceeds to the continuous material strip feeding unit 23 by way of apair of guide rollers 35, 36 and then to a layering table 30. Thelayering table 30 reciprocates on a track 41 laid on a support structure39 by a predetermined stroke.

The material strip 4 guided by said guide rollers 35, 36 is then fedthrough a guide roller 34 to either the pressing roll 28 or 29 of thecontinuous material strip feeding unit 23 alternately.

When the layering table 30 moves in the direction of arrow XL, a lot ofstrips of the adhesive agent are applied onto the upper surface of thelayered portion 31 of the material strip 4 on the layering table 30 bymeans of the set of applicators 26 of the adhesive agent applying unit24 in the operating position 24A. The layered portion 31 of the materialstrip 4 is clamped by a pair of clamps 37, 38 at the opposite ends. Thestripes of the adhesive agent are applied as shown in FIG. 5 runningalong the longitudinal direction of the layering table as indicated byarrow A. In the embodiment, the stripes are arranged at a pitch P of23.1 mm, each of the strips has a width C of 5.8 mm in FIG. 5, but theinvention is not limited to the pitch and width.

In this mode of operation, the material strip 4 moves in the continuousmaterial strip feeding unit 23 along the solid line. A length of thematerial strip 4 is pressed by the pressing roll 28 in its operationposition 28A against the upper surface of the layered portions 31 of thematerial strip 4 onto which the adhesive agent has just been applied bythe adhesive agent applying unit 24. The length of the material strip 4is clamped at the rear end by the clamp 37.

When the layering table 30 turns its moving direction and moves in thedirection of arrow XR, the applicator 27 of a lot of parallel secondstripes of the adhesive agent applying unit 25 now located in itsoperating position 25A applies the adhesive agent onto the upper surfaceof the layered portions 31 of the material strip 4. The second stripesof the adhesive agent are arranged at a pitch P of 23.1 mm, and each ofthe stripes has a width C of 5.8 mm as illustrated In FIG. 6. The secondstripes of the adhesive agent are transversely displaced by a half pitchrelative to the first stripes of the adhesive agent as shown in FIG. 6.Immediately thereafter, the material strip 4 indicated by the brokenline in FIG. 2 is pressed against the surface of the layered portions 31by the pressing roll 29 located in its operation position 29A and therear end of the stretch is clamped by the clamp 38.

Then, the above described procedures of operation are repeated until amultilayer structure as illustrated in FIG. 7 is produced. The structurehaving a width B is then cut to the predetermined width D and thenexpanded in the vertical direction to produce a honeycomb structure asillustrated in FIG. 8.

In the second embodiment, the adhesive agent applying units 24, 25 andthe pressing rolls 28, 29 are located close to each other immediatelyabove the upper surface of the layered portions 31 of the material stripon the layering table. Thus, the adhesive agent are applied on saidupper surface of the layered portions 31 in parallel stripes runningalong the longitudinal direction of the layering table and, immediatelythereafter, a stretch of the material strip 4 is folded at the front endunder a constant tension and pressed against the upper surface by one ofthe pressing rolls 28, 29. In an experiment using the embodiment, thematerial strip was made of nonwoven polyester cloth permeable to gas andwater having a weight per unit area of 40 g/m² and a thickness of 0.11mm, a modified olefin type hot-melt adhesive agent is applied by aroll-transfer method to produce a pattern of adhesive agent of parallelstripes arranged at a pitch P of 23.1 mm, each of the strips having awidth C of 5.8 mm, and the honeycomb structure has a cell size of 10 mm.

FIG. 3 shows a third embodiment of the invention. In this embodiment, apair of adhesive agent applying units 5, 6, a pair of back-up rolls 7, 8corresponding to the adhesive agent applying units 5, 6, and a pair ofpressing rolls 19, 20 located oppositely relative to the feeding orifice9 for a material strip 4 and immediately above the upper surface of alayering table 12 are same as those of the first embodiment. Theadhesive agent applying units 5, 6, the back-up rolls 7, 8, and pressingrolls 19, 20 are fitted to a roll housing stand 42 which acts as thecontinuous material strip feeding unit 3.

The roll housing stand 42 is so designed as to reciprocate by apredetermined stroke in an concerted manner with the layering table 12which also reciprocates by a predetermined stroke on a track 45 laid ona support structure 43. The pressing rolls 19, 29 are disposedimmediately above an upper surface of layered portions 46 of thematerial strip 4 on the layering table 12 so that the operation ofapplying the adhesive agent and that of pressing the uppermost layer ofthe layered portions 46 can be carried out continuously and repeatedly.

Since the structure and the functions of each of the components housedin the continuous material strip feeding unit 3 of this embodiment areidentical to those of the counterpart of the first embodiment of FIG. 1,description for them will be omitted here and only those components thatare different from those of the first embodiment will be describedbelow.

When the layering table 12 is moving in the direction of arrow XL inFIG. 3, the roll housing stand 42 disposed above the upper surface ofthe layered portions 46 of the material strip 4 moves in the oppositedirection as indicated by arrow XR, and the adhesive agent applying unit6 longitudinally (indicated by arrow A) applies the adhesive agent onthe side 16 of the material strip in parallel stripes as illustrated inFIG. 5. In an experiment using this embodiment, an epoxy type adhesiveagent was applied by using a gravure coating technique onto a materialstrip 4 which had a thickness of 30 micron and which was hard vinylchloride strip at a pitch P of 3.5 mm, each stripe having a width C of0.87 mm.

The side 16 is pressed to the upper surface of the layered portion 46 onthe layering table 12 by the pressing roll 19 due to the movement of thelayering table 12 in a direction of arrow XL.

When, on the other hand, the roll housing stand 42 is moving in thedirection of arrow XL, the second stripes of the adhesive agent areapplied to the side 17. As illustrated in FIG. 6, the second stripes ofthe adhesive agent are displaced transversely by a half pitch from thefirst strips (illustrated in FIG. 5) of the adhesive agent. The side 17is pressed onto the layered portion 46 of the material strip 4 by thepressing roll 20 due to the movement of the layering table 12rightwardly. By repeating the above described procedures of operation, alaminate for honeycomb structure as illustrated in FIG. 7 can beprepared.

The laminate for honeycomb structure was heated and pressed at 50° C.under a pressure of 8 kg/cm² for 60 minutes to thermoset the adhesiveagent. The laminate was then cut to a predetermined length and softenedin warm water to produce honeycomb structure as illustrated in FIG. 8.

Since the roll housing stand 42 and the layering table 12 move inopposite directions in this embodiment, they show a boosted relativemoving speed to consequently raise the rate of producing multilayerstructures, and the stroke of the layering table may be reduced.

In the above experiment, a hard vinyl chloride strip having a thicknessof 30 micron could be used without any problem as a material strip forproducing laminate for honeycomb structures. Consequently a highly denselaminate for honeycomb structure having a cell size of 1.5 mm could beprepared.

FIG. 4 illustrates a fourth embodiment of the invention. The adhesiveagent applying units 24, 25, the applicators 26, 27 provided to theadhesive agent applying units 24, 25, and the pressing rolls 28, 29disposed oppositely relative to a material strip feeding orifice 40 andadjacent to the adhesive agent applying units 24, 25 are the same asthose in the continuous material strip feeding unit 23 of the embodimentof FIG. 2. These components are housed in and pivotally attached to aroll housing stand 48 of a frame means. The roll housing stand 48 actsas the continuous material strip feeding unit.

The roll housing stand 48 is capable of reciprocating on a track 49 laidon a support structure 47 by a predetermined stroke in the directionsindicated by arrows XL and XR in FIG. 4 in a concerted manner with saidlayering table 30 that also reciprocates on another track 46 also laidon the support structure 47. The pressing rolls 28, 29 are disposedimmediately above a layered portion 50 of the material strip 4 laid onthe layering table 30 in order to alternately and continuously presslengths of the material strip 4 newly and successively laid on thelayered portions 50 of the material strip 4 to the upper surface ofwhich the adhesive agent is applied.

Because the operations of each of the components of this embodiment forfeeding the material strip 4 and applying thereto the adhesive agent aresimilar to those of the embodiment of FIG. 2, description for them willbe omitted here and only those components that are different from theabove embodiments will be described hereinafter.

When the layering table 30 is moving on the track 46 in the direction ofarrow XL in FIG. 4, the adhesive agent is applied to the upper surfaceof the layered portions 50 of the material strip 4 by the adhesive agentapplying unit 24 to form a pattern of parallel stripes running of theadhesive agent in the direction of arrow A of FIG. 5 at a pitch P of 14mm, each stripe having a width of 3.5 mm, while the roll housing stand48 is moving on the track 49 in the direction of arrow XR of FIG. 4. Theinvention is not limited to the above pitch and the width.

During this operation in which the layering table 30 is moving in thedirection of arrow XL in FIG. 4, by means of the pressing roll 28, theopposite surface of the surface 32 with the adhesive agent is pressedagainst an upper surface of the layered portion 50 (the surface appliedwith the a lot of stripes of the adhesive agent as illustrated in FIG.5) on the layering table 30 so as to press the material stripe 4 to thelayered portion 50.

When, on the other hand, the layering table 30 is moving in thedirection of arrow XR, the roll housing stand 48 moves in the directionof arrow XL so that the second stripes of the adhesive agenttransversely displaced by a half pitch as illustrated in FIG. 6 isapplied by the adhesive agent applying unit 25 onto the upper surface ofthe layered portion 50 of the material strip 4.

The second adhesive agent is applied to the side 32 as illustrated inFIG. 6 and, immediately thereafter, another stretch of the materialstrip 4 coming down along the other feeding path indicated by a brokenline in FIG. 4 is pressed against the upper surface of the layeredportion 50 that carries strips of adhesive agent by the pressing roll 29with the side 33 of the material strip 4 facing upwardly.

Then, the above procedures of operation are repeated to produce amultilayer structure as illustrated in FIG. 7.

Since the roll housing stand 48 and the layering table 30 moved inopposite directions relative to each other in this embodiment, theirrelative speed with regard to each other is boosted to raise the rate offolding and pressing the material strip to form a multilayer structurewithout adversely affecting the precision with which it is formed.

In an experiment using the embodiment of FIG. 4, a laminate forhoneycomb structure having a honeycomb cell size of 6.0 mm was preparedby using polyester nonwoven cloth having a thickness of 50 micron and aweight per unit area of 30 g/m² for the material strip 4 and a modifiedolefin type hot-melt adhesive agent, which is applied to the materialstrip 4 in parallel stripes at a pitch P of 14.0 mm, each stripe havinga width C of 3.8 mm.

In the above described embodiments, the adhesive agent is applied to amaterial strip 4 longitudinally along direction indicated by arrow A inFIG. 5. However, it may be easily understood that the adhesive agent mayalternatively be applied to a material strip transversely, or in adirection perpendicular to the direction of arrow A by using one or morethan one applicator rolls provided with a number of grooves arranged onthe outer peripheral surface of each of the rolls arranged along thegenerating line of the peripheral surface as typically illustrated inFIGS. 9 and 10.

In the above described embodiments, a modified olefin type hot-meltadhesive agent or an epoxy type adhesive agent is used. However, theadhesive agent may be appropriately use for the purpose of the presentinvention also include synthetic resin type adhesives, emulsion typeadhesives and synthetic rubber type adhesives. These adhesives may beapplied by using a roll transfer or gravure coating technique.

As described above, a method and an apparatus according to the inventionare advantageous over conventional methods and apparatuses in that amultilayer structure can be prepared from a continuous material stripwithout cutting it into unit sheets and the folded and layered materialstrip can be accurately aligned simply by controlling the oppositeturning points of the reciprocating layering table and clamping thefolded areas of the material strip.

Additionally, since the adhesive agent applying units and the pressingrolls as well as other appropriate components are arranged near thelayering table and operated in a manner that allows the operation offolding and layering a material strip to be carried out continuously sothat an additional length of the material strip is quickly laid on thesurface of the already layered portions of the material strip afterapplying the adhesive agent thereto, a molten hot-melt type adhesiveagent can be effectively and efficiently used without losing its effectwith time.

Thus, a method and an apparatus according to the invention allows theuse of a highly viscous molten hot-melt type adhesive agent withoutpermitting it to pass through the material strip from a side to theother thereof even if the material strip is thin and made of a soft andcoarse material so that high quality laminate for honeycomb structuresmay be manufactured.

Since the time from applying the adhesive agent to laying an additionallength of the material strip to the layered portions thereof isminimized, a hot-melt adhesive agent of the type that will quickly becooled and hardened when brought to contact with any other object can beused and any additional steps of heating and pressing the layeredmaterial strip are not required. Additionally, the use of a diluent toregulate the viscosity of the adhesive agent is also not required.

When the continuous material strip feeding unit of an apparatusaccording to the invention is realized in the form of a roll housingstand integral with the support structure and disposed above thelayering table in such a manner that said roll housing stand and saidlayering table moves in opposite directions relative to each other,their relative speed with regard to each other is remarkably increasedto raise the rate of folding and layering the material strip and hencethe overall efficiency of manufacturing laminate for honeycombstructures.

Since the time from applying the adhesive agent to layering anadditional length of the material strip is significantly reduced withsuch an arrangement, a highly viscous hot-melt type adhesive agent canbe effectively used to produce a sufficient adhesiveness even if a verysmall amount of the adhesive agent is used.

In addition to the above described advantages of the present invention,it is also advantageous for a method and an apparatus according to theinvention that the adhesive agent can be applied either longitudinallyor transversely relative to the running direction of the material stripby simply altering the arrangement of the adhesive agent applying units.

It is also advantageous for a method and an apparatus according to theinvention that an adhesive agent of an appropriate type can be selectedfrom a number of different adhesive agents depending on the type of thematerial strip to be used.

What is claimed is:
 1. A method of manufacturing laminate for ahoneycomb structure by moving a layering table and a roll housing stand,the roll housing stand moving in a first direction and the layeringtable moving in an opposite second direction, said roll housing standincluding means for feeding the material strip from one roll, a pair ofpressing/bonding rolls and a pair of means for applying a plurality ofstripes of the adhesive agent, said method comprising the steps of(a)feeding a material strip by a predetermined length to an uppermostsurface of a folded and layered material strip disposed on a layeringtable by forwardly moving said layering table by a stroke correspondingto said length in a first direction and by rearwardly moving said rollhousing stand in a second opposite direction, (b) applying a pluralityof first stripes of an adhesive agent to either the uppermost surface ofthe layered material strip on said layering table or a lower surface ofthe material strip being fed by one of a pair of means for applying aplurality of stripes of the adhesive agent when said layering table ismoved forwardly and said roll housing stand is moved rearwardly, (c)immediately pressing the material strip being fed to the layeredmaterial strip by one of a pair of pressing/bonding rolls when saidlayering table is moved forwardly and said roll housing stand is movedrearwardly, (d) folding a rear end of said length of the material strip,(e) feeding the material strip by the length to a new upper surface ofthe folded and layered material strip disposed on the layering table bymoving rearwardly said table by said stroke and by moving forwardly saidroll housing stand, (f) applying a plurality of second stripes of anadhesive agent to either said new upper surface or the lower surface ofthe material strip being fed by the other of said pair of means forapplying a plurality of stripes of the adhesive agent when said layeringtable is moved rearwardly and said roll housing stand is movedforwardly, said second stripes being displaced transversely by a halfpitch from the first stripes of the adhesive agent, (g) immediatelypressing the material strip being fed to the folded and layered materialstrip by the other of said pair of pressing/bonding rolls when saidlayering table is moved forwardly and said roll housing stand is movedrearwardly, (h) holding the rear end of said length of the materialstrip, and (i) repeating the above steps (a) to (h).
 2. The methodaccording to claim 1, whereina plurality of stripes of the adhesiveagent are applied to a lower surface of the material strip being fed. 3.The method according to claim 1, whereina plurality of stripes of theadhesive agent are applied to an upper surface of the layered strip onsaid layering table.